Floating thumb is a relatively rare hand deformity, also known as floating thumb. Although it is called floating thumb, it is not completely floating, there is still a loose skin tube connecting the thumb to the palm of the hand, there is no metacarpal bone in it, and it can’t exert any force, it can only swing with the swing of the hand, and it looks like a small meatball hanging on the hand. The floating thumb has sensation, it has nerves and blood vessels inside, the sensory functions are all there, and it will know the pain if it is accidentally pinched. It is a pity to remove such a thumb for bunionization. Floating bunions can be preserved, but the surgical operation is extremely complicated. In the past, the main surgical procedure used for the preservation of floating bunions was metatarsal bone reconstruction, i.e., reconstruction of the first metacarpal bone from the foot. Metatarsal bone reconstruction can be categorized into two types, namely, free direct phalanx and anastomotic phalanx with vascularized tip, and this type of surgery has certain requirements for the age of the child for surgery, which should not be too young. From the doctor’s point of view, we recommend the child to have the surgery earlier, between 6 months and 1 year old is better, because this time is the child’s thumb function establishment stage, this time to do the surgery in the thumb function establishment will be more smooth, and because of the child’s age, so the child will not have deformity characteristics of the memory, which is more conducive to the child’s physical and mental development. Nowadays, we are using the technique of hemi-metacarpal bone grafting to reconstruct the five fingers, taking part of the bone from the second metacarpal to reconstruct the first metacarpal, and the child can be operated around 6 months to 1 year old, which can help the child to build up the function of the thumb at an earlier stage, and the results are more ideal after the operation.